| Message ID | 20240528164829.2105447-2-willy@infradead.org |
|---|---|
| State | New |
| Headers | show |
| Series | Start moving write_begin/write_end out of aops | expand |
Hi Matthew, kernel test robot noticed the following build warnings: [auto build test WARNING on linus/master] [also build test WARNING on v6.10-rc1 next-20240528] [cannot apply to tytso-ext4/dev jack-fs/for_next] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch#_base_tree_information] url: https://github.com/intel-lab-lkp/linux/commits/Matthew-Wilcox-Oracle/fs-Introduce-buffered_write_operations/20240529-005213 base: linus/master patch link: https://lore.kernel.org/r/20240528164829.2105447-2-willy%40infradead.org patch subject: [PATCH 1/7] fs: Introduce buffered_write_operations config: arm64-allnoconfig (https://download.01.org/0day-ci/archive/20240529/202405290745.X6owMB05-lkp@intel.com/config) compiler: aarch64-linux-gcc (GCC) 13.2.0 reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240529/202405290745.X6owMB05-lkp@intel.com/reproduce) If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot <lkp@intel.com> | Closes: https://lore.kernel.org/oe-kbuild-all/202405290745.X6owMB05-lkp@intel.com/ All warnings (new ones prefixed by >>): >> mm/filemap.c:4097: warning: Function parameter or struct member 'fsdata' not described in '__filemap_write_iter' mm/filemap.c:4146: warning: Function parameter or struct member 'ops' not described in 'filemap_write_iter' >> mm/filemap.c:4146: warning: Function parameter or struct member 'fsdata' not described in 'filemap_write_iter' vim +4097 mm/filemap.c ^1da177e4c3f41 Linus Torvalds 2005-04-16 4072 e4dd9de3c66bc7 Jan Kara 2009-08-17 4073 /** 1e90da36c016f4 Matthew Wilcox (Oracle 2024-05-28 4074) * __filemap_write_iter - write data to a file e4dd9de3c66bc7 Jan Kara 2009-08-17 4075 * @iocb: IO state structure (file, offset, etc.) 8174202b34c30e Al Viro 2014-04-03 4076 * @from: iov_iter with data to write 1e90da36c016f4 Matthew Wilcox (Oracle 2024-05-28 4077) * @ops: How to inform the filesystem that a write is starting/finishing. e4dd9de3c66bc7 Jan Kara 2009-08-17 4078 * e4dd9de3c66bc7 Jan Kara 2009-08-17 4079 * This function does all the work needed for actually writing data to a e4dd9de3c66bc7 Jan Kara 2009-08-17 4080 * file. It does all basic checks, removes SUID from the file, updates e4dd9de3c66bc7 Jan Kara 2009-08-17 4081 * modification times and calls proper subroutines depending on whether we e4dd9de3c66bc7 Jan Kara 2009-08-17 4082 * do direct IO or a standard buffered write. e4dd9de3c66bc7 Jan Kara 2009-08-17 4083 * 9608703e488cf7 Jan Kara 2021-04-12 4084 * It expects i_rwsem to be grabbed unless we work on a block device or similar e4dd9de3c66bc7 Jan Kara 2009-08-17 4085 * object which does not need locking at all. e4dd9de3c66bc7 Jan Kara 2009-08-17 4086 * e4dd9de3c66bc7 Jan Kara 2009-08-17 4087 * This function does *not* take care of syncing data in case of O_SYNC write. e4dd9de3c66bc7 Jan Kara 2009-08-17 4088 * A caller has to handle it. This is mainly due to the fact that we want to 9608703e488cf7 Jan Kara 2021-04-12 4089 * avoid syncing under i_rwsem. a862f68a8b3600 Mike Rapoport 2019-03-05 4090 * a862f68a8b3600 Mike Rapoport 2019-03-05 4091 * Return: a862f68a8b3600 Mike Rapoport 2019-03-05 4092 * * number of bytes written, even for truncated writes a862f68a8b3600 Mike Rapoport 2019-03-05 4093 * * negative error code if no data has been written at all e4dd9de3c66bc7 Jan Kara 2009-08-17 4094 */ 1e90da36c016f4 Matthew Wilcox (Oracle 2024-05-28 4095) ssize_t __filemap_write_iter(struct kiocb *iocb, struct iov_iter *from, 1e90da36c016f4 Matthew Wilcox (Oracle 2024-05-28 4096) const struct buffered_write_operations *ops, void *fsdata) ^1da177e4c3f41 Linus Torvalds 2005-04-16 @4097 { ^1da177e4c3f41 Linus Torvalds 2005-04-16 4098 struct file *file = iocb->ki_filp; fb5527e68d4956 Jeff Moyer 2006-10-19 4099 struct address_space *mapping = file->f_mapping; ^1da177e4c3f41 Linus Torvalds 2005-04-16 4100 struct inode *inode = mapping->host; 44fff0fa08ec5a Christoph Hellwig 2023-06-01 4101 ssize_t ret; ^1da177e4c3f41 Linus Torvalds 2005-04-16 4102 44fff0fa08ec5a Christoph Hellwig 2023-06-01 4103 ret = file_remove_privs(file); 44fff0fa08ec5a Christoph Hellwig 2023-06-01 4104 if (ret) 44fff0fa08ec5a Christoph Hellwig 2023-06-01 4105 return ret; ^1da177e4c3f41 Linus Torvalds 2005-04-16 4106 44fff0fa08ec5a Christoph Hellwig 2023-06-01 4107 ret = file_update_time(file); 44fff0fa08ec5a Christoph Hellwig 2023-06-01 4108 if (ret) 44fff0fa08ec5a Christoph Hellwig 2023-06-01 4109 return ret; ^1da177e4c3f41 Linus Torvalds 2005-04-16 4110 2ba48ce513c4e5 Al Viro 2015-04-09 4111 if (iocb->ki_flags & IOCB_DIRECT) { 44fff0fa08ec5a Christoph Hellwig 2023-06-01 4112 ret = generic_file_direct_write(iocb, from); ^1da177e4c3f41 Linus Torvalds 2005-04-16 4113 /* fbbbad4bc2101e Matthew Wilcox 2015-02-16 4114 * If the write stopped short of completing, fall back to fbbbad4bc2101e Matthew Wilcox 2015-02-16 4115 * buffered writes. Some filesystems do this for writes to fbbbad4bc2101e Matthew Wilcox 2015-02-16 4116 * holes, for example. For DAX files, a buffered write will fbbbad4bc2101e Matthew Wilcox 2015-02-16 4117 * not succeed (even if it did, DAX does not handle dirty fbbbad4bc2101e Matthew Wilcox 2015-02-16 4118 * page-cache pages correctly). ^1da177e4c3f41 Linus Torvalds 2005-04-16 4119 */ 44fff0fa08ec5a Christoph Hellwig 2023-06-01 4120 if (ret < 0 || !iov_iter_count(from) || IS_DAX(inode)) 44fff0fa08ec5a Christoph Hellwig 2023-06-01 4121 return ret; 44fff0fa08ec5a Christoph Hellwig 2023-06-01 4122 return direct_write_fallback(iocb, from, ret, 1e90da36c016f4 Matthew Wilcox (Oracle 2024-05-28 4123) filemap_perform_write(iocb, from, ops, fsdata)); fb5527e68d4956 Jeff Moyer 2006-10-19 4124 } 44fff0fa08ec5a Christoph Hellwig 2023-06-01 4125 1e90da36c016f4 Matthew Wilcox (Oracle 2024-05-28 4126) return filemap_perform_write(iocb, from, ops, fsdata); ^1da177e4c3f41 Linus Torvalds 2005-04-16 4127 } 1e90da36c016f4 Matthew Wilcox (Oracle 2024-05-28 4128) EXPORT_SYMBOL(__filemap_write_iter); ^1da177e4c3f41 Linus Torvalds 2005-04-16 4129 e4dd9de3c66bc7 Jan Kara 2009-08-17 4130 /** 1e90da36c016f4 Matthew Wilcox (Oracle 2024-05-28 4131) * filemap_write_iter - write data to a file e4dd9de3c66bc7 Jan Kara 2009-08-17 4132 * @iocb: IO state structure 8174202b34c30e Al Viro 2014-04-03 4133 * @from: iov_iter with data to write e4dd9de3c66bc7 Jan Kara 2009-08-17 4134 * 1e90da36c016f4 Matthew Wilcox (Oracle 2024-05-28 4135) * This is a wrapper around __filemap_write_iter() to be used by most e4dd9de3c66bc7 Jan Kara 2009-08-17 4136 * filesystems. It takes care of syncing the file in case of O_SYNC file 9608703e488cf7 Jan Kara 2021-04-12 4137 * and acquires i_rwsem as needed. 1e90da36c016f4 Matthew Wilcox (Oracle 2024-05-28 4138) * a862f68a8b3600 Mike Rapoport 2019-03-05 4139 * Return: 1e90da36c016f4 Matthew Wilcox (Oracle 2024-05-28 4140) * * negative error code if no data has been written at all or if a862f68a8b3600 Mike Rapoport 2019-03-05 4141 * vfs_fsync_range() failed for a synchronous write a862f68a8b3600 Mike Rapoport 2019-03-05 4142 * * number of bytes written, even for truncated writes e4dd9de3c66bc7 Jan Kara 2009-08-17 4143 */ 1e90da36c016f4 Matthew Wilcox (Oracle 2024-05-28 4144) ssize_t filemap_write_iter(struct kiocb *iocb, struct iov_iter *from, 1e90da36c016f4 Matthew Wilcox (Oracle 2024-05-28 4145) const struct buffered_write_operations *ops, void *fsdata) ^1da177e4c3f41 Linus Torvalds 2005-04-16 @4146 { ^1da177e4c3f41 Linus Torvalds 2005-04-16 4147 struct file *file = iocb->ki_filp; 148f948ba877f4 Jan Kara 2009-08-17 4148 struct inode *inode = file->f_mapping->host; ^1da177e4c3f41 Linus Torvalds 2005-04-16 4149 ssize_t ret; ^1da177e4c3f41 Linus Torvalds 2005-04-16 4150 5955102c9984fa Al Viro 2016-01-22 4151 inode_lock(inode); 3309dd04cbcd2c Al Viro 2015-04-09 4152 ret = generic_write_checks(iocb, from); 3309dd04cbcd2c Al Viro 2015-04-09 4153 if (ret > 0) 1e90da36c016f4 Matthew Wilcox (Oracle 2024-05-28 4154) ret = __filemap_write_iter(iocb, from, ops, fsdata); 5955102c9984fa Al Viro 2016-01-22 4155 inode_unlock(inode); ^1da177e4c3f41 Linus Torvalds 2005-04-16 4156 e259221763a404 Christoph Hellwig 2016-04-07 4157 if (ret > 0) e259221763a404 Christoph Hellwig 2016-04-07 4158 ret = generic_write_sync(iocb, ret); ^1da177e4c3f41 Linus Torvalds 2005-04-16 4159 return ret; ^1da177e4c3f41 Linus Torvalds 2005-04-16 4160 } 1e90da36c016f4 Matthew Wilcox (Oracle 2024-05-28 4161)
On Tue, May 28, 2024 at 05:48:22PM +0100, Matthew Wilcox (Oracle) wrote: > Start the process of moving write_begin and write_end out from the > address_space_operations to their own struct. > > The new write_begin returns the folio or an ERR_PTR instead of returning > the folio by reference. It also accepts len as a size_t and (as > documented) the len may be larger than PAGE_SIZE. > > Pass an optional buffered_write_operations pointer to various functions > in filemap.c. The old names are available as macros for now, except > for generic_file_write_iter() which is used as a function pointer by > many filesystems. If using the new functions, the filesystem can have > per-operation fsdata instead of per-page fsdata. The model looks good, but buffered_write_operations sounds a little too generic for a helper that hopefully won't have too many users in the end.
diff --git a/Documentation/filesystems/locking.rst b/Documentation/filesystems/locking.rst index e664061ed55d..e62a8a83ea9e 100644 --- a/Documentation/filesystems/locking.rst +++ b/Documentation/filesystems/locking.rst @@ -413,6 +413,29 @@ path after ->swap_activate() returned success. ->swap_rw will be called for swap IO if SWP_FS_OPS was set by ->swap_activate(). +buffered_write_operations +========================= + + struct folio *(*write_begin)(struct file *, struct address_space *, + loff_t pos, size_t len, void **fsdata); + size_t (*write_end)(struct file *, struct address_space *, + loff_t pos, size_t len, size_t copied, + struct folio *folio, void **fsdata); + +For write_begin, 'len' is typically the remaining length of the write, +and is not capped to PAGE_SIZE. For write_end, len will be limited so +that pos + len <= folio_pos(folio) + folio_size(folio). copied will +not exceed len. pos + len will not exceed MAX_LFS_FILESIZE. + +write_begin may return an ERR_PTR. write_end may return a number less +than copied if it needs the caller to retry from an earlier position in +the file. It cannot signal an error; that must be done by write_begin(). + +write_begin should lock the folio and increase its refcount. write_end +should unlock it and drop the refcount, possibly after setting it +uptodate (it can only use folio_end_read() for this if it knows the folio +was not previously uptodate; probably best not to use it). + file_lock_operations ==================== diff --git a/fs/jfs/file.c b/fs/jfs/file.c index 01b6912e60f8..9c62445ea6be 100644 --- a/fs/jfs/file.c +++ b/fs/jfs/file.c @@ -4,8 +4,7 @@ * Portions Copyright (C) Christoph Hellwig, 2001-2002 */ -#include <linux/mm.h> -#include <linux/fs.h> +#include <linux/pagemap.h> #include <linux/posix_acl.h> #include <linux/quotaops.h> #include "jfs_incore.h" diff --git a/fs/ramfs/file-mmu.c b/fs/ramfs/file-mmu.c index b45c7edc3225..5de2a232d07f 100644 --- a/fs/ramfs/file-mmu.c +++ b/fs/ramfs/file-mmu.c @@ -24,8 +24,7 @@ * caches is sufficient. */ -#include <linux/fs.h> -#include <linux/mm.h> +#include <linux/pagemap.h> #include <linux/ramfs.h> #include <linux/sched.h> diff --git a/fs/ufs/file.c b/fs/ufs/file.c index 6558882a89ef..b557d4a14143 100644 --- a/fs/ufs/file.c +++ b/fs/ufs/file.c @@ -24,7 +24,7 @@ * ext2 fs regular file handling primitives */ -#include <linux/fs.h> +#include <linux/pagemap.h> #include "ufs_fs.h" #include "ufs.h" diff --git a/include/linux/fs.h b/include/linux/fs.h index 0283cf366c2a..4c6c2042cbeb 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -3115,10 +3115,7 @@ extern int generic_file_rw_checks(struct file *file_in, struct file *file_out); ssize_t filemap_read(struct kiocb *iocb, struct iov_iter *to, ssize_t already_read); extern ssize_t generic_file_read_iter(struct kiocb *, struct iov_iter *); -extern ssize_t __generic_file_write_iter(struct kiocb *, struct iov_iter *); -extern ssize_t generic_file_write_iter(struct kiocb *, struct iov_iter *); extern ssize_t generic_file_direct_write(struct kiocb *, struct iov_iter *); -ssize_t generic_perform_write(struct kiocb *, struct iov_iter *); ssize_t direct_write_fallback(struct kiocb *iocb, struct iov_iter *iter, ssize_t direct_written, ssize_t buffered_written); diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index ee633712bba0..2921c1cc6335 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -18,6 +18,27 @@ struct folio_batch; +struct buffered_write_operations { + struct folio *(*write_begin)(struct file *, struct address_space *, + loff_t pos, size_t len, void **fsdata); + size_t (*write_end)(struct file *, struct address_space *, + loff_t pos, size_t len, size_t copied, + struct folio *folio, void **fsdata); +}; + +ssize_t filemap_write_iter(struct kiocb *, struct iov_iter *, + const struct buffered_write_operations *, void *fsdata); +ssize_t __filemap_write_iter(struct kiocb *, struct iov_iter *, + const struct buffered_write_operations *, void *fsdata); +ssize_t filemap_perform_write(struct kiocb *, struct iov_iter *, + const struct buffered_write_operations *, void *fsdata); + +ssize_t generic_file_write_iter(struct kiocb *, struct iov_iter *); +#define generic_perform_write(kiocb, iter) \ + filemap_perform_write(kiocb, iter, NULL, NULL) +#define __generic_file_write_iter(kiocb, iter) \ + __filemap_write_iter(kiocb, iter, NULL, NULL) + unsigned long invalidate_mapping_pages(struct address_space *mapping, pgoff_t start, pgoff_t end); diff --git a/mm/filemap.c b/mm/filemap.c index 382c3d06bfb1..162ac110c423 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -95,7 +95,7 @@ * ->invalidate_lock (filemap_fault) * ->lock_page (filemap_fault, access_process_vm) * - * ->i_rwsem (generic_perform_write) + * ->i_rwsem (filemap_perform_write) * ->mmap_lock (fault_in_readable->do_page_fault) * * bdi->wb.list_lock @@ -3975,7 +3975,8 @@ generic_file_direct_write(struct kiocb *iocb, struct iov_iter *from) } EXPORT_SYMBOL(generic_file_direct_write); -ssize_t generic_perform_write(struct kiocb *iocb, struct iov_iter *i) +ssize_t filemap_perform_write(struct kiocb *iocb, struct iov_iter *i, + const struct buffered_write_operations *ops, void *fsdata) { struct file *file = iocb->ki_filp; loff_t pos = iocb->ki_pos; @@ -3985,11 +3986,10 @@ ssize_t generic_perform_write(struct kiocb *iocb, struct iov_iter *i) ssize_t written = 0; do { - struct page *page; - unsigned long offset; /* Offset into pagecache page */ - unsigned long bytes; /* Bytes to write to page */ + struct folio *folio; + size_t offset; /* Offset into pagecache folio */ + size_t bytes; /* Bytes to write to page */ size_t copied; /* Bytes copied from user */ - void *fsdata = NULL; offset = (pos & (PAGE_SIZE - 1)); bytes = min_t(unsigned long, PAGE_SIZE - offset, @@ -4012,19 +4012,33 @@ ssize_t generic_perform_write(struct kiocb *iocb, struct iov_iter *i) break; } - status = a_ops->write_begin(file, mapping, pos, bytes, + if (ops) { + folio = ops->write_begin(file, mapping, pos, bytes, &fsdata); + if (IS_ERR(folio)) { + status = PTR_ERR(folio); + break; + } + } else { + struct page *page; + status = a_ops->write_begin(file, mapping, pos, bytes, &page, &fsdata); - if (unlikely(status < 0)) - break; + if (unlikely(status < 0)) + break; + folio = page_folio(page); + } if (mapping_writably_mapped(mapping)) - flush_dcache_page(page); + flush_dcache_folio(folio); - copied = copy_page_from_iter_atomic(page, offset, bytes, i); - flush_dcache_page(page); + copied = copy_folio_from_iter_atomic(folio, offset, bytes, i); + flush_dcache_folio(folio); - status = a_ops->write_end(file, mapping, pos, bytes, copied, - page, fsdata); + if (ops) + status = ops->write_end(file, mapping, pos, bytes, + copied, folio, &fsdata); + else + status = a_ops->write_end(file, mapping, pos, bytes, + copied, &folio->page, fsdata); if (unlikely(status != copied)) { iov_iter_revert(i, copied - max(status, 0L)); if (unlikely(status < 0)) @@ -4054,12 +4068,13 @@ ssize_t generic_perform_write(struct kiocb *iocb, struct iov_iter *i) iocb->ki_pos += written; return written; } -EXPORT_SYMBOL(generic_perform_write); +EXPORT_SYMBOL(filemap_perform_write); /** - * __generic_file_write_iter - write data to a file - * @iocb: IO state structure (file, offset, etc.) - * @from: iov_iter with data to write + * __filemap_write_iter - write data to a file + * @iocb: IO state structure (file, offset, etc.) + * @from: iov_iter with data to write + * @ops: How to inform the filesystem that a write is starting/finishing. * * This function does all the work needed for actually writing data to a * file. It does all basic checks, removes SUID from the file, updates @@ -4077,7 +4092,8 @@ EXPORT_SYMBOL(generic_perform_write); * * number of bytes written, even for truncated writes * * negative error code if no data has been written at all */ -ssize_t __generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from) +ssize_t __filemap_write_iter(struct kiocb *iocb, struct iov_iter *from, + const struct buffered_write_operations *ops, void *fsdata) { struct file *file = iocb->ki_filp; struct address_space *mapping = file->f_mapping; @@ -4104,27 +4120,29 @@ ssize_t __generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from) if (ret < 0 || !iov_iter_count(from) || IS_DAX(inode)) return ret; return direct_write_fallback(iocb, from, ret, - generic_perform_write(iocb, from)); + filemap_perform_write(iocb, from, ops, fsdata)); } - return generic_perform_write(iocb, from); + return filemap_perform_write(iocb, from, ops, fsdata); } -EXPORT_SYMBOL(__generic_file_write_iter); +EXPORT_SYMBOL(__filemap_write_iter); /** - * generic_file_write_iter - write data to a file + * filemap_write_iter - write data to a file * @iocb: IO state structure * @from: iov_iter with data to write * - * This is a wrapper around __generic_file_write_iter() to be used by most + * This is a wrapper around __filemap_write_iter() to be used by most * filesystems. It takes care of syncing the file in case of O_SYNC file * and acquires i_rwsem as needed. + * * Return: - * * negative error code if no data has been written at all of + * * negative error code if no data has been written at all or if * vfs_fsync_range() failed for a synchronous write * * number of bytes written, even for truncated writes */ -ssize_t generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from) +ssize_t filemap_write_iter(struct kiocb *iocb, struct iov_iter *from, + const struct buffered_write_operations *ops, void *fsdata) { struct file *file = iocb->ki_filp; struct inode *inode = file->f_mapping->host; @@ -4133,13 +4151,18 @@ ssize_t generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from) inode_lock(inode); ret = generic_write_checks(iocb, from); if (ret > 0) - ret = __generic_file_write_iter(iocb, from); + ret = __filemap_write_iter(iocb, from, ops, fsdata); inode_unlock(inode); if (ret > 0) ret = generic_write_sync(iocb, ret); return ret; } + +ssize_t generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from) +{ + return filemap_write_iter(iocb, from, NULL, NULL); +} EXPORT_SYMBOL(generic_file_write_iter); /**
Start the process of moving write_begin and write_end out from the address_space_operations to their own struct. The new write_begin returns the folio or an ERR_PTR instead of returning the folio by reference. It also accepts len as a size_t and (as documented) the len may be larger than PAGE_SIZE. Pass an optional buffered_write_operations pointer to various functions in filemap.c. The old names are available as macros for now, except for generic_file_write_iter() which is used as a function pointer by many filesystems. If using the new functions, the filesystem can have per-operation fsdata instead of per-page fsdata. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> --- Documentation/filesystems/locking.rst | 23 ++++++++ fs/jfs/file.c | 3 +- fs/ramfs/file-mmu.c | 3 +- fs/ufs/file.c | 2 +- include/linux/fs.h | 3 -- include/linux/pagemap.h | 21 ++++++++ mm/filemap.c | 77 +++++++++++++++++---------- 7 files changed, 97 insertions(+), 35 deletions(-)